1. Field of the Invention
This invention relates to polyester bicomponent continuous filaments, more particularly to yarns of such filaments which have high crimp level, high node frequency and node interval constancy, and to a process for making such yarns.
2. Description of Background Art
Continuous bicomponent filaments and yarns of poly(ethylene terephthalate) and poly(trimethylene terephthalate) have been disclosed in U.S. Pat. No. 3,617,379 and Published Applications US2002/0025433, US2001/0055683, and WO02/063080. However, such yarns can be too nonuniform or twist-lively to perform well in downstream processing.
U.S. Pat. Nos. 2,985,995 and 3,115,695 describe jets that can be used to entangle ‘flat’ fibers, and U.S. Pat. No. 4,100,725 discloses tightly entangled yarns with long entanglement nodes, but such yarns can have inadequate stretch properties.
Polyester bicomponent yarns having high crimp levels, little or no twist, and frequent entanglement nodes at highly constant intervals are still needed, as is a process to make them.